Background: The Global Burden of Disease study provided international statistics on the burden of diseases, combining mortality and disability, that can be used for priority setting and policy making. However, there are concerns about the universality of the disability weights used. We undertook a study to investigate the stability of such weighting in different countries and informant groups.
Methods: 241 key informants (health professionals, policy makers, people with disabilities, and their carers) from 14 countries were asked to rank 17 health conditions from most disabling to least disabling. Kruskal-Wallis ANOVA was used to test for differences in ranking between countries or informant groups and Kendall tau-B correlations to measure association between different rank orders.
Findings: For 13 of 17 health conditions, there were significant (p<0.05) differences in ranking between countries; in the comparison of informant groups, there were significant differences for five of the 17 health conditions. The overall rank order in the present study was, however, almost identical to the ranking of the Global Burden of Disease study, which used a different method. Most of the rank correlations between countries were between 0.50 and 0.70 (average 0.61 [95% CI 0.59-0.64]). The average correlation of rank orders between different informant groups was 0.76.
Interpretation: Rank order of disabling effects of health conditions is relatively stable across countries, informant groups, and methods. However, the differences are large enough to cast doubt on the assumption of universality of experts' judgments about disability weights. Further studies are needed because disability weights are central to the calculation of disability-adjusted life years.